As a foreword; I’m not a tradesmen, not even close. I have a crack at stuff and probably know enough about a few things to not be competent, but just dangerous.
This is also a bit of an essay, I thought that showing my though process for this might help others in the future.
I've been wanting to upgrade the factory intercooler on the GU now for a while. I recently did a trip down to Victoria to do some volunteer flood work in Victoria and as part of that towed down a heavy utility trailer and had a Rooftop tent on the Patrol.
Through the entire trip I found my EGT’s were consistently sitting around 400 degrees on flat sections of road and going up any sort of decent incline would see them spike into the danger zone of around 600-650+. I was consistently backing off going up hills and had to drive the thing like I was nursing it. The peak of this was coming into Sydney travelling through the Hawksbury region I found myself being overtaken going up a hill by a Sims scrap metal truck.
I should say at this point that the vehicle has been tuned, and I suspect it’s a bit spicy. I’m happy with the power of the vehicle (~155 hp at the wheels on 33’s) but I think that the AFR’s are probably well up there to get that.
As a mid trip remedy I picked up a pair of 250mm Maridyne fans and bodged up a mounting system in a servo carpark- I used zip ties to hold a fan under the standard intercooler and a bit of cardboard to make some ducting. This dropped the EGT’s substantially and prevented the stock intercooler from heat soaking as quickly- it also seemed to help it recover much faster as well.
My long-term aim has always been to fit a larger intercooler and since I’ve got some Fraser Island trips planned before the end of the year, I decided to do it sooner rather than later.
I decided on a Top Mount cooler as opposed to a front mount for several reasons, those being;
-Ease of fabrication of pipework. From initial research the routing of pipework for a front mount is convoluted on a GU. The conventional wisdom seems to be that pipework goes through the passenger side wheel arch which I deemed to be unacceptable both from a durability perspective, but also I think it looks untidy (I accept that this is a subjective judgement and some may not have a problem with that).
-The amount of accessories I’ve already got in the front of the car that would either have to be moved, or would block flow to the cooler there (Winch and winch control box, twin spotties and an existing separate cooler for the transmission). To my mind these hinder the performance of a top mount.
-Blocking airflow to the radiator. I didn’t like that in addition to all the stuff mentioned above that’s already hindering flow that I’d effectively be putting another large heat exchanger in the road that my thermo fan would have to pull air through.
-Protection. Top mounts are typically more protected against rocks/ sticks etc. than front mounts and are also less susceptible to getting full of mud/ dirt etc.
Any design choice is a trade-off. Front mounts are certainly superior from a performance perspective. Aa top mount is also a pain in the neck to work around in the engine bay, although since I don’t have a second battery under the bonnet, I’ve got a bit more room than usual.
The cooler I went with was the cheapest bar and plate intercooler I could find on eBay and I’ll link it down the bottom for future reference if anyone is interested.
I should say at the outset that I wanted to use dual Maridyne fans on the cooler. This makes it much more difficult to get clearance and the job without these would be a lot easier.
The first step was to remove all the factory brackets and fabricate up a mount for the new cooler. We decided to use 12mm round bar and 50x3 EA steel sections to produce the desired shape. The fans were zipped tied onto the bottom of the cooler to make sure that there was sufficient clearance between them and the electrical plugs on top of the injectors. My intercooler ended up in a similar position to the stock cooler being located approximately 180mm from the firewall. (which is a little bit further forward that some of the others that I’ve seen on the forums- as I have fans underneath this position was required to clear the injectors however.
After fabricating a bracket that held the cooler in the correct spot the bonnet scoop was examined, and a template drawn. This template was then used to get an idea of where the scoop would need to go- The Colorado scoop has quite a long “lip” that needs to be accommodated for when cutting the hole.
The bonnet was then cut out and the scoop test fitted. It turns out that the lip was slightly fouling on the front of the cooler and so using a flap wheel I trimmed the plastic back about 10mm to get it to clear.
As of today, that’s where I’m up to. I’m heading into town today to get a can of paint that will be colour matched to the car and we’ll give the scoop a coat of paint.
Once I’ve got the scoop back I’ll affix it to the car and set the final position. The brackets mounting the cooler are still only tacked so they can be moved if necessary to accommodate the position of the scoop slightly. Once everything is set in position I’ll start fabricating the hot and cold side piping to the cooler. Finally, I’ll cut off the mounting bung for the MAP sensor and weld it onto the end tank of the new cooler. I’m also intending to put an air temp sensor in there wired to an Arduino to control my thermos fans.
This is also a bit of an essay, I thought that showing my though process for this might help others in the future.
I've been wanting to upgrade the factory intercooler on the GU now for a while. I recently did a trip down to Victoria to do some volunteer flood work in Victoria and as part of that towed down a heavy utility trailer and had a Rooftop tent on the Patrol.
Through the entire trip I found my EGT’s were consistently sitting around 400 degrees on flat sections of road and going up any sort of decent incline would see them spike into the danger zone of around 600-650+. I was consistently backing off going up hills and had to drive the thing like I was nursing it. The peak of this was coming into Sydney travelling through the Hawksbury region I found myself being overtaken going up a hill by a Sims scrap metal truck.
I should say at this point that the vehicle has been tuned, and I suspect it’s a bit spicy. I’m happy with the power of the vehicle (~155 hp at the wheels on 33’s) but I think that the AFR’s are probably well up there to get that.
As a mid trip remedy I picked up a pair of 250mm Maridyne fans and bodged up a mounting system in a servo carpark- I used zip ties to hold a fan under the standard intercooler and a bit of cardboard to make some ducting. This dropped the EGT’s substantially and prevented the stock intercooler from heat soaking as quickly- it also seemed to help it recover much faster as well.
My long-term aim has always been to fit a larger intercooler and since I’ve got some Fraser Island trips planned before the end of the year, I decided to do it sooner rather than later.
I decided on a Top Mount cooler as opposed to a front mount for several reasons, those being;
-Ease of fabrication of pipework. From initial research the routing of pipework for a front mount is convoluted on a GU. The conventional wisdom seems to be that pipework goes through the passenger side wheel arch which I deemed to be unacceptable both from a durability perspective, but also I think it looks untidy (I accept that this is a subjective judgement and some may not have a problem with that).
-The amount of accessories I’ve already got in the front of the car that would either have to be moved, or would block flow to the cooler there (Winch and winch control box, twin spotties and an existing separate cooler for the transmission). To my mind these hinder the performance of a top mount.
-Blocking airflow to the radiator. I didn’t like that in addition to all the stuff mentioned above that’s already hindering flow that I’d effectively be putting another large heat exchanger in the road that my thermo fan would have to pull air through.
-Protection. Top mounts are typically more protected against rocks/ sticks etc. than front mounts and are also less susceptible to getting full of mud/ dirt etc.
Any design choice is a trade-off. Front mounts are certainly superior from a performance perspective. Aa top mount is also a pain in the neck to work around in the engine bay, although since I don’t have a second battery under the bonnet, I’ve got a bit more room than usual.
The cooler I went with was the cheapest bar and plate intercooler I could find on eBay and I’ll link it down the bottom for future reference if anyone is interested.
I should say at the outset that I wanted to use dual Maridyne fans on the cooler. This makes it much more difficult to get clearance and the job without these would be a lot easier.
The first step was to remove all the factory brackets and fabricate up a mount for the new cooler. We decided to use 12mm round bar and 50x3 EA steel sections to produce the desired shape. The fans were zipped tied onto the bottom of the cooler to make sure that there was sufficient clearance between them and the electrical plugs on top of the injectors. My intercooler ended up in a similar position to the stock cooler being located approximately 180mm from the firewall. (which is a little bit further forward that some of the others that I’ve seen on the forums- as I have fans underneath this position was required to clear the injectors however.
After fabricating a bracket that held the cooler in the correct spot the bonnet scoop was examined, and a template drawn. This template was then used to get an idea of where the scoop would need to go- The Colorado scoop has quite a long “lip” that needs to be accommodated for when cutting the hole.
The bonnet was then cut out and the scoop test fitted. It turns out that the lip was slightly fouling on the front of the cooler and so using a flap wheel I trimmed the plastic back about 10mm to get it to clear.
As of today, that’s where I’m up to. I’m heading into town today to get a can of paint that will be colour matched to the car and we’ll give the scoop a coat of paint.
Once I’ve got the scoop back I’ll affix it to the car and set the final position. The brackets mounting the cooler are still only tacked so they can be moved if necessary to accommodate the position of the scoop slightly. Once everything is set in position I’ll start fabricating the hot and cold side piping to the cooler. Finally, I’ll cut off the mounting bung for the MAP sensor and weld it onto the end tank of the new cooler. I’m also intending to put an air temp sensor in there wired to an Arduino to control my thermos fans.
